Equation of State: Manhattan Project Developments and Beyond

Abstract

The hydrodynamic response of materials under extreme conditions of pressure, temperature and strain is dependent on the equation of state of the matter in all its states of existence. The Trinity plutonium implosion device development required the Los Alamos research community to advance the understanding of equations of state further and faster than ever before. The unpredicted high yield from the Trinity fission device explosion and the push to design the "Super" thermonuclear device initiated 75 years of unprecedented research and technological progress in equation of state development. This article describes the progress made on equation of state development during and since the Manhattan Project at Los Alamos.

Indications of flat bands driving the δ to α volume collapse of plutonium

“…With regard to the Pu equation of state ( 57 ), our findings complement electronic structure calculations, which are considered to provide insight into the relative stability of the various phases of Pu at ( 55 ). Under the assumption that the δ and α phases preserve their electronic structure when doped with 2 atomic % Ga the latter usually referred to as -Pu when substituted with 2% Ga ( 3 ), our findings inform us of how the entropy in Pu should be accurately modeled as a function of temperature.…”

Thirty Minutes Before the Dawn

“…As work progressed, confidence increased. See Martz et al 15 and Crockett and Freibert, 16 this issue, on the remarkable properties of plutonium that needed to be understood. The design innovations in the Theoretical Division that led to the "Christy gadget," a spherical solid plutonium core, are described in this issue by Chadwick and Chadwick.…”

An integrated EOS, pore‐crush, strength and damage model framework for near‐field ground‐shock

“…[11][12][13] Improvements in geomaterial EOS continues to be a topic of active research, especially as measurement techniques advance. 14 Notably, better descriptions of temperature, 15,16 multiphase mixtures and phase changes, 17,18 and the influence of dry and water-filled porosity 19,20 remain active areas of research.…”

“…The importance and challenge of including the effect of air‐filled porosity crushing out, that is, “pore‐crush,” has also been identified for some time, with various approaches proposed 11–13 . Improvements in geomaterial EOS continues to be a topic of active research, especially as measurement techniques advance 14 . Notably, better descriptions of temperature, 15,16 multiphase mixtures and phase changes, 17,18 and the influence of dry and water‐filled porosity 19,20 remain active areas of research.…”